The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    RIAA EQ Mod - PAS 2

    Share

    8xlaxx

    Posts : 18
    Join date : 2016-12-10

    RIAA EQ Mod - PAS 2

    Post by 8xlaxx on Fri Jan 27, 2017 11:41 am

    If anyone has performed the RIAA EQ mod to their PAS2, could you please advise on proper capacitor matching, suggested brands, AND parts numbers if you used a vendor ? (ie. Digi-key,...no affiliation.)
    Thank you!
    avatar
    j beede

    Posts : 386
    Join date : 2011-02-07
    Location : California

    Re: RIAA EQ Mod - PAS 2

    Post by j beede on Fri Jan 27, 2017 2:24 pm

    I purchase the majority of my capacitors from Antique Electronic Supply. Excellent inventory, excellent service, no minimum. They sell the usual industrial brands--Sprague, Illinois, Mallory, CE, Solen, and others. Heads up: I discovered that the labeling on some CE types could be damaged/removed by common solvents.

    The caps you will need are inexpensive. Buy more than needed and then "match" values using a simple cap meter. If you intend to use the stock PCB (or clone) you will probably find that many boutique brands take up too much space. I was unable to find every exact value so installed some paralleled sets--one cap on top of the PCB, one below. It worked out well.

    I found that getting rid of that input selector "rat's nest" and the miserable caps located on it was the single best upgrade to the PAS. That preamp now operates without crosstalk--like a "real" preamp.


    avatar
    peterh

    Posts : 797
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: RIAA EQ Mod - PAS 2

    Post by peterh on Fri Jan 27, 2017 5:40 pm

    8xlaxx wrote:If anyone has performed the RIAA EQ mod to their PAS2, could you please advise on proper capacitor matching, suggested brands, AND parts numbers if you used a vendor ? (ie. Digi-key,...no affiliation.)
    Thank you!

    What RIAA mod are you talking about ? is it :
    http://www.curcioaudio.com/Dynaco%20PAS%20RIAA%20EQ%20Correction%20Mod.pdf

    Then read :
    http://www.audioregenesis.com/documents/PAS_Phono.pdf

    and then enjoy your PAS2 "as is"

    8xlaxx

    Posts : 18
    Join date : 2016-12-10

    Re: RIAA EQ Mod - PAS 2

    Post by 8xlaxx on Fri Jan 27, 2017 11:04 pm

    Thank you Peter. I thoroughly read the article. The screwdriver is staying put on the bench. Will just have to sacrifice the Tape Out low-end frequency compromise/response.

    Again, appreciate the link.
    avatar
    j beede

    Posts : 386
    Join date : 2011-02-07
    Location : California

    Re: RIAA EQ Mod - PAS 2

    Post by j beede on Sat Jan 28, 2017 3:39 pm

    Regardless of what you do regarding the RIAA circuit... by all means replace your input selector and its associated wiring. If you are still running the stock power supply--that needs to go too.

    Replacing the input selector is an ideal time to replace the stock RCA I/O board. This is not a trivial job but makes the PAS perform like a much more modern preamp.
    avatar
    peterh

    Posts : 797
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: RIAA EQ Mod - PAS 2

    Post by peterh on Sat Jan 28, 2017 4:30 pm

    j beede wrote:Regardless of what you do regarding the RIAA circuit... by all means replace your input selector and its associated wiring. If you are still running the stock power supply--that needs to go too.

    Replacing the input selector is an ideal time to replace the stock RCA I/O board. This is not a trivial job but makes the PAS perform like a much more modern preamp.
    Why replace the input selector ? Motivate please.

    Sponsored content

    Re: RIAA EQ Mod - PAS 2

    Post by Sponsored content


      Current date/time is Fri Jun 23, 2017 4:27 am